CN114024292A

CN114024292A - Fault tolerant solid state power controller

Info

Publication number: CN114024292A
Application number: CN202111427434.6A
Authority: CN
Inventors: D·A·埃利奥特
Original assignee: GE Aviation Systems Ltd
Current assignee: GE Aviation Systems Ltd
Priority date: 2017-01-16
Filing date: 2018-01-16
Publication date: 2022-02-08
Also published as: GB2558655A; CN108321764A; US20180205220A1; US11201462B2; GB2558655B; GB201700715D0

Abstract

The invention discloses a fault-tolerant solid-state power controller. A solid state power controller for delivering power to a load is provided. The solid state power controller comprises a set of sections, wherein each section comprises at least one power switching block. The solid state power controller further includes a protection circuit in each section. The protection circuit is configured to prevent a fault occurring in one power switching block from propagating to other sections, other power switching blocks, or the load.

Description

Fault tolerant solid state power controller

Technical Field

The present invention relates to Solid State Power Controllers (SSPCs). More particularly, the present invention relates to fault tolerant SSPCs.

Background

Power distribution systems typically include one or more power distribution units (EPDUs) that deliver power from one or more sources (e.g., generators and/or batteries) to load circuits. For example, a typical EPDU includes high power transmission components that can dynamically change their configuration, allowing the EPDU components and load circuits to adapt to changing conditions.

These EPDUs may also dynamically change their configuration to prioritize power according to the most necessary load when the required power exceeds the available supply. Furthermore, EPDUs are protected from hazardous conditions, such as excessive power flow due to faults in the load or distribution wiring, which may otherwise cause significant situations, including electrical fires.

SSPCs have been developed to emulate the primary relay and breaker functions required by a typical EPDU as well as for providing additional functionality, such as monitoring power flow for diagnostic purposes. Initially, limitations of semiconductor technology, and in particular semiconductor power switching devices, limited SSPCs to lower voltages (e.g., 28V DC or 115V AC) at current levels up to about 30A.

Simulating the higher current SSPC required for the contactor required to switch high currents can be implemented by parallelizing a large number of power switching components. However, the addition of components comes at the cost of reliability. Furthermore, some of the common failure modes of these components may cause damage to upstream and/or downstream equipment and may even cause an electrical fire.

Disclosure of Invention

Given the foregoing deficiencies, it is desirable to provide SSPC circuitry that includes a large number of components and is characterized by high parallelism and without compromising reliability and the ability to isolate faults. The examples characterized herein help solve or mitigate these and other problems known in the art.

Typical SSPCs rated at continuous currents of up to about 50A are used in many applications, including aircraft power distribution, and have proven to provide a number of well-known benefits over equivalent electromechanical alternatives such as circuit breakers and relays. However, such applications also require higher current power controllers to control and deliver power from sources such as aircraft generators.

Examples disclosed herein provide a high current SSPC that can automatically isolate a faulty power switching block, allowing the SSPC to continue to provide its primary functionality, but with a reduced level of performance from the SSPC's highest performance. However, in typical applications, such as aircraft flight, this performance degradation does not prevent the aircraft from continuing its mission.

The various aspects limit the failure of a component to the particular power switching block in which the failure occurs, thereby not allowing the SSPC to lose its functionality. For example, when a failure occurs, the non-failed component is protected from excessive electrical stress, thereby maintaining its integrity. Other aspects isolate the failed elements so that overall SSPC functionality is maintained to the extent that the SSPC can still be in use (for at least a short time) with minimal performance degradation. Furthermore, the advantageous aspects of the present invention can be achieved with minimal complexity and therefore at minimal cost.

One exemplary aspect provides a solid state power controller for delivering power to a load. The solid state power controller comprises a set of sections, wherein each section comprises at least one power switching block. The solid state power controller further includes a protection circuit in each section. The protection circuit is configured to prevent a fault occurring in one power switching block from propagating to other sections, other power switching blocks, or loads.

Another exemplary aspect provides a solid state power controller for delivering power to a load. The solid state power controller includes a power switching element and a set of first, second, and third protection circuits. The first protection circuit is configured to isolate a first fault occurring on a power line of the first set of power switching elements from reaching the second set of power switching elements. Further, the second protection circuit is configured to isolate a second fault occurring in the load from reaching the set of power switching elements. And the third protection circuit is configured to isolate a third fault occurring in the power switching elements included in one set from reaching another set of power switching elements.

Another exemplary aspect provides a solid state power controller for delivering power to a load. The solid state power controller includes a power switching block that includes a set of power switching elements. The solid state power controller further includes a protection circuit configured to prevent a fault occurring in a power switching element of the set of power switching elements from propagating to other power switching elements of the set of power switching elements.

Technical solution 1. a solid state power controller for delivering power to a load, comprising:

a set of sections, wherein each section comprises at least one power switching block;

a protection circuit in each section, wherein the protection circuit is configured to prevent a fault occurring in one power switching block from propagating to other sections, other power switching blocks, or the load.

Technical solution 2. the solid-state power controller according to technical solution 1, wherein: the fault is a short circuit.

Technical solution 3. the solid-state power controller according to any one of technical solutions 1 or 2, wherein: the fault is characterized by a current of the solid state power controller exceeding a predetermined threshold.

Technical solution 4. the solid-state power controller according to technical solution 3, wherein: the current flows through at least one of the power switching block and the load.

Technical solution 5. the solid-state power controller according to any one of the preceding technical solutions, wherein: the protection circuit includes at least one fuse.

Technical solution 6. the solid-state power controller according to any one of the preceding technical solutions, wherein: the power switching block includes a set of power switching elements.

Technical solution 7. the solid-state power controller according to technical solution 6, wherein: the power switching elements from the set of power switching elements are selected from the group consisting of: metal oxide semiconductor field effect transistors, junction field effect transistors, bipolar junction transistors, insulated gate bipolar junction transistors, triacs, and thyristors.

Technical solution 8 a solid state power controller for delivering power to a load, comprising:

a set of power switching elements; and

a first protection circuit, a second protection circuit and a third protection circuit;

wherein the first protection circuit is configured to isolate a first fault occurring on a power line of the first set of power switching elements from reaching the second set of power switching elements; and is

Wherein the second protection circuit is configured to isolate a second fault occurring in the load from reaching the set of power switching elements.

Technical solution 9. the solid-state power controller according to technical solution 8, wherein: the third protection circuit is configured to isolate a third fault occurring in the power switching elements included in one set from reaching another set of power switching elements.

The solid-state power controller according to claim 9, wherein: the first fault, the second fault, and the third fault are each short circuits.

Technical solution 11 the solid-state power controller according to any one of technical solutions 9 or 10, wherein: the first fault, the second fault, and the third fault are each a current of the solid state power controller exceeding a predetermined threshold.

Technical solution 12 the solid-state power controller according to technical solution 11, wherein: the current flows through at least one of the sets of power switching elements, and the load by propagating through the solid state power controller circuit.

Technical solution 13. the solid-state power controller according to claim 12, wherein: the power switching element is selected from the group consisting of: metal oxide semiconductor field effect transistors, junction field effect transistors, bipolar junction transistors, insulated gate bipolar junction transistors, triacs, and thyristors.

Technical solution 14. a solid state power controller for delivering power to a load, comprising:

a power switching block comprising a set of power switching elements;

a protection circuit configured to prevent a fault occurring in a power switching element of the set of power switching elements from propagating to other power switching elements of the set of power switching elements.

Technical solution 15 the solid-state power controller according to claim 14, wherein: the protection circuit is further configured to prevent the fault from propagating to the load.

Technical solution 16 the solid-state power controller according to any one of technical solutions 14 or 15, wherein: the solid state power controller further includes other power switching blocks.

The solid-state power controller according to claim 16, wherein: the protection circuit is further configured to prevent the fault from propagating to the other power switching blocks.

Technical solution 18 the solid-state power controller according to any one of technical solutions 14 to 17, wherein: the solid state power controller further includes an overvoltage protection circuit configured to protect the set of power switching elements.

Technical means 19 the solid-state power controller according to claim 18, wherein: the solid state power controller further includes a controller configured to drive the set of power switching elements.

Technical solution 20 the solid-state power controller according to any one of technical solutions 14 to 19, wherein: the protection circuit includes at least one of a fuse and a resistor.

Additional features, modes of operation, advantages, and other aspects of various examples are described below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the specific examples described herein. These examples are presented for illustrative purposes only. Additional examples or modifications to the disclosed examples will be apparent to persons skilled in the relevant art based on the teachings provided.

Drawings

The illustrative embodiments may take form in various components and arrangements of components. Illustrative embodiments are shown in the drawings, and like reference numerals may indicate corresponding or similar parts throughout the several views of the drawings. The drawings are only for purposes of illustrating embodiments and are not to be construed as limiting the invention. The novel aspects of this invention will become apparent to those skilled in the relevant art in view of the following instructive description of the drawings.

FIG. 1 illustrates a conventional SSPC.

FIG. 2 illustrates another example of a conventional SSPC.

FIG. 3 illustrates an SSPC constructed in accordance with aspects described herein.

FIG. 4 illustrates an SSPC in accordance with aspects described herein.

Detailed Description

Although the illustrative embodiments are described herein with respect to particular applications, it should be understood that the invention is not limited thereto. Those skilled in the art with access to the teachings provided herein will recognize additional applications, modifications, and embodiments within the scope thereof and additional fields in which the invention may be of significant utility.

In the following description, it is assumed that a power switching element (e.g., MOSFET, JFET, BJT, IGBT, triac, or thyristor) may experience a short circuit or open circuit fault between its terminals. Nevertheless, other failure modes are also considered, i.e. failure modes in which the switching element exhibits a change in conductivity between its terminals with respect to a predetermined threshold. One of ordinary skill in the art will readily recognize that such intermediate failure modes may be detected by monitoring current and/or voltage and comparing the current and/or voltage to a threshold, among other methods.

Fig. 1 illustrates a conventional SSPC 100. In the conventional SSPC100, the power flow originates from a power source 102 to an external load 104; the delivery of power to the load 104 is controlled using a switching element, namely a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) 106. The conventional SSPC100 includes a controller 108 configured to enable or inhibit power flow to the load 104 by varying the voltage applied to the gate of the MOSFET 106.

The controller 108 may be implemented using a microcontroller or equivalent circuit block with appropriate interface and computing functionality. The conventional SSPC100 includes a driver 100 disposed between the output of a controller 108 and the gate of a MOSFET 106. The driver 110 is typically an amplifier whose design and characteristics are optimized to provide an electrical interface between the controller 108 and the gate of the MOSFET 106.

The potential difference of the control MOSFET 106 is between its gate and its source. Thus, because the source of MOSFET 106 is at the same potential as load 104, driver 110 is often switched to the power input line of load 104. However, the controller 108 may switch to local ground (not shown) or to the power input line of the load 104 (as shown) to provide sufficient isolation, or level shifting circuitry is included in the controller 108 to accommodate this flexibility. The conventional SSPC100 can be communicatively coupled to a remote device or system through a network communication interface 116, the circuitry (not shown) of which can be switched to local ground relative to the power input line of the load 104. Certain metrics, such as fault occurrence, current level, power dissipation, and SSPC status, may be detected and communicated through the network communication interface 106.

The conventional SSPC100 includes a current sensor 112 that provides real-time monitoring of current flow to the load 104 to the controller 108 so that the controller 108 can detect an over-current condition and shut off the MOSFET 106, thereby protecting the current path to the load 104. The conventional SSPC100 further includes a fuse 114 that acts as a backup overcurrent protection device if the SSPC function fails. The precise location of the fuse 114 in the current path from the power source 102 to the load 104 may vary and does not affect its function.

The maximum current rating of the conventional SSPC100, which typically corresponds to an SSPC current rating of 5A, is limited by the MOSFET 106. To obtain a higher SSPC current rating, several MOSFETs can be placed in parallel, as shown in the conventional SSPC200 of FIG. 2. In particular, to service a load 204 that requires more power than the load 104 of fig. 1, the conventional SSPC200 can transfer three times more power from the power source 104 to the load 204 by using three MOSFETs (2061, 2062, and 2063). Each of the three MOSFETs has a gate resistor (i.e.,

gate resistors

2071, 2072, and 2073) disposed at its gate.

The resistances of the gate resistors, each typically about 5 ohms, are selected to be large enough to prevent oscillation and small enough to ensure that the MOSFETs can be effectively switched by the controller 108 and driver 110. Thus, the conventional SSPC200 provides a continuous current capability that is greater than that of the conventional SSPC 100. It is possible to obtain even higher current capability SSPCs by parallelizing more switching elements. For example, a 500A SSPC may be obtained by parallelizing 100 MOSFETs in a manner similar to that shown in fig. 2.

While higher current carrying capacity can be obtained by increasing the number of switching elements in parallel combination, SSPCs implemented in this manner exhibit several problems. From a reliability perspective, the greater the number of power switching elements included in the SSPC, the greater the likelihood of failure of the SSPC.

For example, if one of the switching elements in a parallel combination generates an internal fault, the resulting current may easily damage the other switching elements. Often, such damage on a large scale can cause secondary problems, including arcing, smoke, and/or fire, which can be very dangerous and annoying in some applications, such as during aircraft flight.

FIG. 3 illustrates an exemplary high current capacity SSPC300, according to an embodiment. The SSPC300 alleviates the above-mentioned problems, as well as other problems known in the art, as described in more detail below.

The conventional SSPC300 includes a current sensor 312 that provides real-time monitoring of current flow to the load 304 to the controller 378 so that the controller 108 can detect an over-current condition. Further, the SSPC300 includes nine switching elements (MOSFETs 306-308, 326-328, and 346-348) distributed in groups of three among the

sections

31, 32, and 33. Each section includes an overvoltage protection circuit (313, 301, 381), which may be a Zener diode or a transient voltage suppressor. Generally, the

overvoltage protection circuits

301, 313, and 381 may be implemented using components having clamping characteristics, such as zener diodes or transient voltage suppressors. Further, each group includes gate circuits disposed at each gate of the switching elements and each including a fuse, a gate resistor, and a gate-to-source resistor.

Specifically, the switching elements in section 31 interface with gate

circuitry including fuses

314, 318, and 331,

gate resistors

316, 320, and 324, and gate-to-source resistors 305, 309, and 311 (interface); the switching elements of section 32 interface with gate

circuitry including fuses

329, 331, and 333,

gate resistors

330, 332, and 334, and gate-to-source resistors 335, 336, and 337; and the switching elements of section 33 interface with gate circuitry that includes

fuses

349, 352, and 354,

gate resistors

351, 353, and 355, and gate-to-

source resistors

375, 376, and 377. The SSPC300 further includes a set of drives (310, 340, and 350), each of which is dedicated to one of the

sections

31, 32, and 33.

In the absence of a fault in any switching element, the nine switching elements form a parallel combination that can carry nine times the maximum current rating of a single switching element. Moreover, the SSPC300 includes several structural features as will be described in greater detail below that impart several advantageous aspects; each feature may be used alone or in combination with other features depending on the desired degree of benefit.

One feature includes a set of fuses (383, 385, 387, 389, 390, 391, 392, and 393) that can be used to isolate specific portions of the SSPC300 based on the location of the fault. The current rating of each fuse is selected to provide reliable connection in a fault-free condition and the desired protection in the event of a fault. It should be appreciated that each fuse may be a specific component dedicated for this purpose, or any fusible component or link that provides an equivalent function.

Further, fuse rating herein refers to the maximum current that a fuse can carry, regardless of time limit. Nevertheless, each fuse may carry a current greater than its rated value for a short transient period, but will blow when subjected to a continuous current significantly exceeding its rated value. As an example and not by way of limitation, each fuse in the set of fuses (383, 385, 387, 389, 390, 391, 392, and 393) may have a current rating of approximately 5A.

Each of the

fuses

383 and 385 will isolate a group of three switching elements that are directly connected to the fuse in the event that current flows excessively into the group. This excessive current may be due to a fault such as a short to ground on the circuit board housing the SSPC300 or because one or more of the switching elements in the group failed to open when the controller 378 commanded it to open, so that the entire current through the SSPC300 is limited to the group.

In such a case, either of

fuses

383 and 385 must be designated to reliably carry its fair share of the overall rating of SSPC300 (i.e., about 1/3 of the overall current rating). Nonetheless, if the current is close to the normal maximum current through the SSPC300, either of the

fuses

383 and 385 will blow. Thus, consider that when SSPC300 is commanded to open when connected to load 304, in the event of such a fault, either of

fuses

383 and 385 is likely to blow and isolate the group with the switching element experiencing the short (e.g., the MOSFET experiences a drain-to-source short).

Further, in some embodiments, each of the

fuses

383 and 385 can be replaced by a set of fuses, such as

fuses

387, 389, and 390, to provide additional granularity in the protection architecture of the SSPC 300. Specifically, fuses 387, 389, and 390 perform the same function as

fuses

383 or 385, but each may isolate a single switching element experiencing a fault. In some embodiments, each of the

fuses

387, 389, and 390 will be rated for an appropriate portion (e.g., l/3 as shown) of the single fuse (e.g., fuse 385) it replaces.

The

fuses

391, 392, and 393 are configured to isolate their respective blocks of power switching elements (i.e.,

sections

31, 32, and 33) from the load 304. This isolation capability enables other blocks to continue to operate when one block creates a short to ground. The likelihood of such a short circuit depends on the particular physical implementation of the SSPC300, and thus, the inclusion of

fuses

391, 392, and 393 is optional. Finally, with respect to the SSPC300, as an alternative configuration (not shown), any of the

fuses

391, 392 and 393 may be configured as a set of fuses (e.g., fuses 387, 389, and 390) to isolate the particular switching element in which the fault occurred.

Another advantageous feature of the SSPC300 is provided by a fuse and gate resistor interfacing at the gate of the switching element. Each of the

segments

31, 32 and 33 must be protected from excessive gate-to-source voltages produced at the output of the driver 310, 340 or 350. Thus, the fuses in the gate circuit (e.g., fuses 314, 318, and 322) are used to safely limit transient power flow between the failed gate (which attempts to pass excessive current) and the rest of the gate drive circuit in the segment that includes the gates of the driver (e.g., 310), the voltage protection device (e.g., 313), and the other FETs in the same segment (e.g., 307 and 308 if 306 is a failed device).

Fuses

314, 318, and 322 are selected to be able to absorb transient energy caused by a predictable fault, such as one of the MOSFETs creating a drain to gate short. Furthermore, fuses, along with their respective gate resistors, can be used to limit the time and maximum current to which the MOSFET switching element is exposed in the event of a drain-to-gate short.

In other words, the gate resistor limits the transient fault current to a value that can be handled by the driver components (e.g., 310 and 313) for a short time and not to exceed the gate voltage of other FETs (e.g., 307 and 378) that share the same driver. Furthermore, if the abnormal current continues to flow before the driver component overheats, the fuse may be bypassed.

Thus, drivers 310, 314, and 350 are designated to ensure that their corresponding gate circuits are sufficiently robust and capable of achieving the desired overvoltage protection without the inclusion of additional components. In an alternative configuration (not shown), the gate circuit may be configured to protect the driver as well as the switching element. In an alternative embodiment not shown, the voltage protection device 313 may be omitted if the driver 310 is sufficiently robust.

The first function of the gate resistor is to prevent vibration at the gate of the MOSFET, as previously described with respect to the conventional SSPC 200. However, in the SSPC300, the gate resistor also limits the excess current that the gate circuit can absorb in the event of an internal MOSFET failure, such as a drain-to-gate short. Thus, yet another advantageous feature of the SSPC300 is the assistance provided by the gate resistor.

If the MOSFET generates a gate fault (e.g., a drain-to-gate short) that causes a large amount of gate current to flow, the gate circuit, initially combined with the driver, ensures that the voltage applied to the gate of the MOSFET remains within a predetermined allowable range. However, this fault current may cause rapid heating within certain components of the driver and/or gate circuits. Accordingly, the fuse included in the gate circuit advantageously provides a means for withstanding normal gate current transients and for interrupting the current as and when the persistent current is established, thereby isolating the faulty MOSFET gate and protecting the rest of the SSPC300 from substantial damage.

Additionally, it should be noted that while the gate resistors and fuses are shown in rectangular blocks to indicate that the overall functionality may be implemented with two separate components, in some embodiments it is possible to select a resistor that will fail and create a high impedance or open circuit when subjected to sustained excessive current. Thus, in these embodiments, no fuse is required.

The gate-to-source resistor of the gate circuit ensures that a given MOSFET is turned off in the absence of a gate drive signal, such as when a fuse in the gate circuit is blown. The gate-to-source resistor may be a large resistor (e.g., about 1M ohms) to avoid unnecessarily loading the gate drive circuit.

It should be noted that connecting the gate-to-source resistor as shown in fig. 3 is suitable for an enhancement MOSFET that is non-conductive when its gate-to-source potential is zero. For other types of MOSFETs, a gate-to-source resistor may be connected at one end to the source of the MOSFET and at the other end to a bias voltage source.

The SSPC300 is configured to supply current to the load 304 unidirectionally through the switching element. However, if the polarity across the drain-to-source terminal of the MOSFET changes, the MOSFET will not be able to block current because it includes an intrinsic diode that can become reverse biased due to the change in polarity of the source, which would change across the drain-to-source terminal of the MOSFET if the source 304 were an AC source.

Fig. 4 illustrates an exemplary SSPC400 adapted to support bidirectional current flow configured in accordance with an embodiment. The SSPC400 is configured to drive a load 404 with an AC source 402 that, due to alternating polarity, produces a bidirectional current to the load 404. SSPC400 includes eighteen (i.e., nine pairs of) back-to-back MOSFETs. It should be noted that the bi-directionality of current can also be achieved with the DC source by configuring the external wiring of the SSPC400 accordingly, and thus, the SSPC400 is not limited to operating with an AC source.

The exemplary SSPC400 of fig. 4 includes nine pairs of back-to-back MOSFETs that are connected as if in parallel provided that no fault condition exists. The SSPC400 includes fuse and gate circuits that are similarly configured in the SSPC300, and thus, the previous description of these components applies equally to the SSPC 400. For ease of description, SSPC400 is shown to include MOSFETs connected in three groups of three pairs of MOSFETs per group, but SSPC400 can be easily scaled for a large number of groups and for a large number of pairs of MOSFETs per group.

The SSPC400 includes a collection of drivers (406, 408, 412, 414, 416, 418, and 420) distributed across the

sections

41, 42, and 43, each section being a power switching block configured to accommodate bidirectional current. Each of the drivers is switched to the source terminals of its respective back-to-back MOSFET pair that it drives. As in the case of the SSPC300, the SSPC400 includes a variety of features that can be used alone or in various combinations to create alternative implementations.

Each of the

sections

41 and 42 has an explicit gate overvoltage protection circuit (407, 409, 411, 413, 415 and 417) associated with each MOSFET pair. These overvoltage protection circuits may be implemented using components with clamping characteristics, such as zener diodes. In section 43, these overvoltage protection circuits are omitted in order to illustrate yet another exemplary implementation of the bidirectional power switching block. In such alternative embodiments, the gate driver may be robust enough for the application at hand, and thus, additional overvoltage protection circuitry may not be required.

Furthermore, in yet another variation, section 43 illustrates a single driver (414) configured to drive all MOSFET pair gates (MOSFET pair gates). In such exemplary embodiments of the bidirectional power switching block, the impedance of the driver 414 ensures that a faulty MOSFET of a MOSFET pair cannot damage or disturb the control of other MOSFET pairs.

The exemplary embodiments described herein provide fault tolerant one-way or two-way SSPCs. Several structural features provide varying degrees of protection. Furthermore, exemplary embodiments provide highly parallel circuits in which the number of components subject to excessive voltage and current can be kept to a minimum. Furthermore, the exemplary embodiments allow for the isolation of the failed component while allowing the rest of the circuit to continue to operate.

It will be appreciated by persons skilled in the relevant art that various adaptations and modifications of the above-described embodiments can be configured without departing from the scope and spirit of the invention. It is therefore to be understood that within the scope of the appended claims, the teachings set forth in this disclosure may be practiced otherwise than as specifically described herein. In particular, the teachings presented herein are also applicable to SSPCs that may be used in applications other than aircraft systems.

Claims

1. A solid state power controller for delivering power to a load, comprising:

a set of sections, wherein each section comprises:

at least one power switching block, wherein each power switching block comprises a set of power switching elements, an

A plurality of gate circuits, each gate circuit disposed at a gate of a corresponding power switching element, each gate circuit comprising (i) a gate-to-source resistor and (ii) a first fuse and a gate resistor connected in series, wherein the gate resistor and the gate-to-source resistor are both directly connected to the gate, and wherein in each section the first fuses of the gate circuits are connected together; and

a protection circuit, wherein the protection circuit is configured to prevent a fault occurring in one power switching block from propagating to other sections, to other power switching blocks, or to the load, wherein the protection circuit comprises the plurality of gate circuits and a plurality of second fuses, each second fuse corresponding to one section of the set of sections, and each second fuse connected to a source of the set of power switching elements and configured to isolate the section and the at least one power switching block from the load and other sections upon occurrence of a short circuit to ground in the section.

2. The solid state power controller of claim 1, wherein: the fault is a short circuit.

3. The solid state power controller of any one of claims 1 or 2, wherein: the fault is characterized by a current of the solid state power controller exceeding a predetermined threshold.

4. The solid state power controller of claim 3, wherein: the current flows through at least one of the power switching block and the load.

5. The solid state power controller of claim 1, wherein: the power switching elements from the set of power switching elements are selected from the group consisting of: metal oxide semiconductor field effect transistors, junction field effect transistors, bipolar junction transistors, insulated gate bipolar junction transistors, triacs, and thyristors.

6. A solid state power controller for delivering power to a load, comprising:

a set of sections, wherein each section comprises:

a set of power switching elements; and

a first protection circuit, a second protection circuit, and a third protection circuit, each protection circuit comprising one of the plurality of gate circuits, each gate circuit disposed at a gate of a corresponding power switching element, each gate circuit comprising (i) a gate-to-source resistor and (ii) a first fuse and a gate resistor connected in series, wherein the gate resistor and the gate-to-source resistor are both directly connected to the gate, and wherein the first fuses of the gate circuits are connected together;

wherein the first protection circuit is configured to isolate a first fault occurring on a power line of the first set of power switching elements from reaching the second set of power switching elements;

wherein the second protection circuit is configured to isolate a second fault occurring in the load from reaching the first set of power switching elements and a third set of power switching elements, an

Wherein the first, second and third protection circuits further comprise a plurality of second fuses, each second fuse corresponding to one of the sets of segments, and each second fuse being connected to the source of the set of power switching elements of that segment and configured to isolate the set of power switching elements of that segment from the load and other segments when a short circuit to ground occurs in that segment.

7. The solid state power controller of claim 6, wherein: the third protection circuit is configured to isolate a third fault occurring in the power switching elements included in one set from reaching another set of power switching elements.

8. The solid state power controller of claim 7, wherein: the first fault, the second fault, and the third fault are each short circuits.

9. The solid state power controller of any one of claims 7 or 8, wherein: the first fault, the second fault, and the third fault are each a current of the solid state power controller exceeding a predetermined threshold.

10. The solid state power controller of claim 9, wherein: the current flows through at least one of the sets of power switching elements, and the load by propagating through the solid state power controller circuit.

11. The solid state power controller of claim 10, wherein: the power switching element is selected from the group consisting of: metal oxide semiconductor field effect transistors, junction field effect transistors, bipolar junction transistors, insulated gate bipolar junction transistors, triacs, and thyristors.

12. A solid state power controller for delivering power to a load, comprising:

power switching blocks, and wherein each power switching block comprises a set of power switching elements; and

a protection circuit comprising a gate circuit disposed at each gate of each power switching element, the gate circuit comprising (i) a gate-to-source resistor and (ii) a first fuse and a gate resistor connected in series, wherein the gate resistor and the gate-to-source resistor are both directly connected to the gate and the first fuse of the gate circuit are connected together, an

Wherein the protection circuit is configured to prevent a fault occurring in a power switching element of the set of power switching elements from propagating to other power switching elements of the set of power switching elements, an

Wherein the protection circuit further comprises a second fuse connected to the source of the set of power switching elements and configured to isolate the power switching block from the load and any other power switching blocks in the event of a short circuit to ground in the power switching block.

13. The solid state power controller of claim 12, wherein: the protection circuit is further configured to prevent the fault from propagating to the load.

14. The solid state power controller of any one of claims 12 or 13, wherein: the solid state power controller further includes other power switching blocks.

15. The solid state power controller of claim 14, wherein: the protection circuit is further configured to prevent the fault from propagating to the other power switching blocks.

16. The solid state power controller of any one of claims 12 to 15, wherein: the solid state power controller further includes an overvoltage protection circuit configured to protect the set of power switching elements.

17. The solid state power controller of claim 16, wherein: the solid state power controller further includes a controller configured to drive the set of power switching elements.

18. The solid state power controller of any one of claims 12 to 17, wherein: the protection circuit further includes a resistor.